Means and method of compressing powdered tungstein, tantalum and the like into crucible form



C. A. PFANSTIEHL. 1

MEANS AND METHOD OF COMPRESSING POWDERED TUNGSTEN, TANTALUM, AND THE LIKE m0 CHUCIBLE FORM. APPLICFUION HLED OCT- 24-1916.

1,321, 1 25. Patented Nov. 11, 1919.

I Even/Z01- unrrn earns arnr anion- CARL A. PFANSTIEHL, 0F HIGHLAND PARK, ILLINOIS, ASSIGNOR TO PFALNSTIEHL COMPANY, INC., OF NORTH CHICAGO, ILLINOIS, A CORPORATION OF NEW YORK.

MEANS AND METHOD OF COMPRES$ING IPOVVDIEIIIELEID TUNGSTEN, TANTALUIVI, AND THE LIKE INTO GRUCIBLE FORM.

Specification of Letters Patent.

Patented Nov. Iii, 1919.

Application filed October 24, 1916. Serial No. 127,443.

To all whom it may concern:

Be it known that I, CARL A. PFANs'rIEIiL, a citizen of the United States, residing at Highland Park, in the county of Lake and State of Illinois, have invented a certain new and useful Improvement in Means and Methods of Compressing Powdered Tungsten, Tantalum, and the like into Cruciluc Form, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invention relates to the method of compressing tungsten powder, tantalum powder, magnesium oxid, tantalum oxizl, thorium oxid, and other powders and the like into crucible or other hollowed form and the means or apparatus for carrying out the method. In my co-pending application, Serial No. 113,323, filed August 5, 1916, I describe and claim a solid composed of tungsten powder and having a weight greater than fifteen grams per cubic centimeter. In my present invention the tungsten powder from which the crucible is formed is compressed to substantially the extent referred to to obtain the advantages mentioned in the above entitled application.

The subject matter of the application referred to relates broadly to a solid composed of tungsten powder compressed to a certain degree whereas the present invention contemplates the provision of means and apparatus for compressing the powdered tung sten or tantalum into crucible like form and has for one of its objects the provision of means for compressing all portions of the material uniformly. I

When tungsten and tantalum powder and many other similar powders are subjected to the enormous pressure of from 135 to 160 tons to the square inch the compressed article has a tendency to crumble away or fall apart when the pressure is removed therefrom unless the pressure is withdrawn in such a manner. as to be relieved on all sides of the article simultaneously. In my eo-pending application, Serial No. 124,504, filed October 9, 1916, I describe and claim broadly means for compressing powdered tungsten or tantalum into the form of articles and for relieving compression on the article in a manner so as to prevent its crumbling or falling apart.

My invention consists generally of a, fluid press arranged to press the tungsten or tantalum powder into the desired shape through the medium of a previously formed crucible made up of sheet metal, preferably copper. The powder is placed around the outside of the metal cup or crucible and between the crucible and an expansible die member. The inside of the metal crucible is then subjected to fluid pressure, preferably oil, and caused to expand longitudinally and laterally against the powder. The pressure is then slightly relieved from the inside of the metal cup and the die member permitted to expand, thus relieving the pressure on both the inside and the outside of the powdered tungsten or tantalum. crucible. After the crucible, together with the previously formed copper cup, is taken from the die the me tallic cup is subjected to acid and thus removed from the tungsten or tantalum or other crucible.

These and other objects of my invention will be more clearly brought out in connection with the accompanying drawings wherein Figure 1 is a vertical sectional view of the compressing apparatus showing the powdered metal in place around a previously formed metallic cup;

Fig. 2 is a horizontal sectional view taken along the line 22 of Fig. l and looking in the direction indicated by the arrows; and

Fig. 3 is a perspective view of the finished crucible.

Similar characters of reference indicate similar parts throughout the several views.

The compressing apparatus of my invention consists of a base member 4-l having an upwardly extending piece 5 centrally located within the tapered opening 6 of the base member. As most clearly illustrated in Fig. 1 the wall of the opening 6 tapers downwardly or in other words, has its widest portion at the top and its narrowest at the bottom. Positioned around the wall of the opening 6 and arranged to slide vertically thereon is a plurality of die members 77, as most clearly illustrated in Fig. 2. These die members are so conformed that they form a pocket which contains the shape of the crucible into which the powdered tungsten or tantalum is to be compressed.

A top plate is provided at 8 through which extend the screws 99 threading into the bores 1010 of the base member The top plate 8 when in the position illustrated in Fig. 1 serves to hold the die members in their lowermost position. A tube 11 eX tends through the cover plate 8 and communicates with the opening 12 formed between the several die members 77. This tube 11 is arranged .to receive oil to be compressed and contains the plunger 13 which when moved downwardly (Fig. '1) serves to compress the oil. In the formation of the crucible the powered tungsten or tantalum, or anyother metal, is placed into the opening 12, together with the previously prepared metallic cup 14, preferably made of copper, the powdered material being positioned around the outside of the cup as illustrated. The top plate 8 is then screw threaded onto the base and the interior of the cup let subjected to the oil pressure derived by the downward movement of the plunger 13.

As stated, it is desirable to subject the powdered tungsten to the enormous pressure of from 130 to 160 tons to the square inch and because of this enormous pressure the copper cup 14 is caused to expand in all directions uniformly so that all portions of the tungsten crucible 15 are compressed to the same degree. If now, after the tung sten crucible has been compressed to the desired extent, the pressure is relieved therefrom only from the inside of the cup, such, for example, as relieving the oil pressure, the tungsten crucible will crumble or fall apart due to the fact that the removal of the pressure is not taken care of uniformly. that is, on the outside of the crucible as well as on the inside thereof. To take care of this uniform pressure relief the die members 77 are provided with tapering external walls so that as the oil pressure is gradually relieved. from the inside of the crucible the screws 99 may be withdrawn to permit the die members 7,7 to slide upwardly thus relieving the pressure on the outside of the crucible and on the base thereof as well as on the inside.

After the crucible is thus formed it is removed from the compressing apparatus, together with the copper cup which adheres thereto due to the enormous pressure to which it was subjected, and dipped into a suitable acid for removing the copper from the tungsten or tantalum. After the copper has been removed the crucible assumes the shape and form illustrated in Fig. 3 ready for use. The crucible thus made may be used as a chemical dish in which to melt substances which have a high melting point but which do not alloy with tungsten or tantalum below the melting points of those metals.

If desired, the tungsten, tantalum or other compressed powder vessels may be sintered bymeans of the electric current whereby the metal will become solid. The word crucible as used herein is intended to mean any hollow or irregularly formed body which cannot be equally compressed throughout by pressure in one direction. It is because of the high resistance to slipping of the particles of powder, upon one another under pressure that the herein disclosed method of compression becomes valuable, and it is therefore to be understood that any articles made by this method willbe embraced'by the term crucible as used in this specification.

Having thus described my invention what I claim as new and desire to secure by Letters Patent of the United States is:

1. The method of pressing powder into irregularly formed articles which consists in placing the powder between a metallic cup and a die, and subjecting the interior of the cup to fluid pressure whereby the cup is expanded to compress the powder between it and the die.

2. The method of pressing powder into a desired form which consists in placing the powder between a metallic cup and a die, applying fluid pressure to the interior of the cup whereby the cup is expanded to compress the powder between it and the die, and subjecting the metallic cup to a suitable acid for removing it from the compressed material.

3. The method of pressing powder into I cup the powdered material to be compressed,

and means for subjecting the interior of the cup to fluid pressure to cause expansion of the cup and thus compression of the powdered material into crucible form.

5. Apparatus for compressing powdered tungsten, tantalum, and the like into crucible form comprising a hollow die member' having the outside shape of the finished crucible, a copper cup adapted to be inserted into the hollow die member, the die member being arranged to receive between it and the cup the powdered material to be compressed, and'means for subjecting the interior of the copper cup to fluid pressure to cause expansion of the cup and thus compression of the powdered material into crucible form.

6. A device for compressing powder into crucible form comprising a hollow expansible die member having the outside shape of the finished crucible, a metal cup adapted to be inserted into the hollow die member, the die member being arranged to receive between it and the cup the powdered material to be compressed, and means for subjecting the interior of the cup to fluid pressure to cause expansion of the cup, and thus compression of the powdered material into crucible form.

7. Apparatus for compressing powdered tungsten, tantalum, and the like into irregular form comprising a hollow die member having the outside shape of the finished article, a copper form adapted to be inserted into the hollow die member, the die member being arranged to receive between it and the copper form the powdered material to be compressed, and means for permitting both the inside and outside of the crucible to expand uniformly when the pressure is removed f-rom the inside of the cup.

8. A device for compressing powder into crucible form comprising a hollow multipart die member having the outside shape of the finished article, a soft metal cup having substantially the same shape as the inside of the finished crucible and adapted to be inserted into the hollow die member to leave a space between said die member and said cup for thereception of the powdered material, and means for subjecting the interior of the cup to fluid pressure to cause expansion of the cup and thus compression of the powdered material within the die.

9. Apparatus for compressing powdered material into the form of a receptacle, comprising a hollow die member having the outside shape of the finished crucible, a copper cup having substantially the same shape as the inside of the finished article, said cup being adapted to be inserted into the hollow die member to leave a space between the die member and said cup for the reception of the powdered material, and means for subjecting the interior of the cup to fluid pressure for expanding the cup and compressing thepowder.

In witness whereof, I hereunto subscribe my name this 5th day of October, A. D. 1916.

CARL A. PFANSTIEHL.

Witnesses:

CLARENCE W. BALKE, MARGARET GRoBBEN. 

